The Hijacker's Choice

A small twin-prop commuter plane was hijacked by a desperate animal rights extremist who vowed to kill one of the passengers to demonstrate his serious intentions.
There were two passengers present, a microbiologist and a yeast geneticist.
The hijacker gave each one two minutes to explain why they shouldn't be killed. The microbiologist (who studied bacteria) talked for 1 minute 59 seconds explaining that he studies bacteria, bacteria are model organisms for the study of genetics and physiology etc. etc. and finished with an emotional, bacteria-laden plea which had the hijacker in tears. When he was done, they turned to the yeast geneticist who said:

- let me explain to you why yeast genetics is an important discipline...

but he was interrupted by the microbiologist who exclaimed:

- Shoot me! Shoot me!